ast: Update strict error check for def func

Currently compiler strict error check will fail for default functions that contain a plain variable argument as the check will report an unused variable. This change attempts to provide a hint on how to pass that check. Signed-off-by: Ashutosh Narkar <[email protected]>
open-policy-agent · Jul 28, 2023 · a929115 · a929115
1 parent 3423cb1
commit a929115
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/ast/compile.go b/ast/compile.go
@@ -2236,7 +2236,11 @@ func (c *Compiler) rewriteLocalVars() {
 				// Report an error for each unused function argument
 				for arg := range unusedArgs {
 					if !arg.IsWildcard() {
-						c.err(NewError(CompileErr, rule.Head.Location, "unused argument %v", arg))
+						if rule.Default {
+							c.err(NewError(CompileErr, rule.Head.Location, "unused default function argument %v. (hint: use _ (wildcard variable) instead)", arg))
+						} else {
+							c.err(NewError(CompileErr, rule.Head.Location, "unused argument %v", arg))
+						}
 					}
 				}
 			}

diff --git a/ast/compile_test.go b/ast/compile_test.go
@@ -5518,6 +5518,18 @@ func TestCheckUnusedFunctionArgVars(t *testing.T) {
 				},
 			},
 		},
+		{
+			note: "unused default function argvar",
+			module: `package test
+			default func(x) := 0`,
+			expectedErrors: Errors{
+				&Error{
+					Code:     CompileErr,
+					Location: NewLocation([]byte("func(x) := 0"), "", 2, 12),
+					Message:  "unused default function argument x. (hint: use _ (wildcard variable) instead)",
+				},
+			},
+		},
 	}
 
 	t.Helper()